The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones,[1] or as a pair the sitting bones,[2] is a large posterior bony protruberance on the superior ramus of the ischium. It marks the lateral boundary of the pelvic outlet.

Ischial tuberosity
Capsule of hip-joint (distended). Posterior aspect. (Ischial tuberosity visible at bottom left.)
Latintuber ischiadicum, tuberositas ischiadica
Anatomical terms of bone

When sitting, the weight is frequently placed upon the ischial tuberosity.[3] The gluteus maximus provides cover in the upright posture, but leaves it free in the seated position.[4] The distance between a cyclist's ischial tuberosities is one of the factors in the choice of a bicycle saddle.

Divisions edit

The tuberosity is divided into two portions: a lower, rough, somewhat triangular part, and an upper, smooth, quadrilateral portion.

  • The lower portion is subdivided by a prominent longitudinal ridge, passing from base to apex, into two parts:
  • The upper portion is subdivided into two areas by an oblique ridge, which runs downward and outward:

Additional images edit

See also edit

Notes edit

  1. ^ M.D, John R. Schultz (October 28, 2019). "Sit Bones Pain (aka Sitz Bone)". Centeno-Schultz Clinic. Retrieved April 12, 2020.
  2. ^ Sills, Franklyn (2004). Craniosacral Biodynamics: The Primal Midline and the Organization of the Body (revised, illustrated ed.). Berkeley, CA: North Atlantic Books. p. 99. ISBN 1-55643-390-5.
  3. ^ Goossens (2005), pp 895–982
  4. ^ Platzer (2004), p 236

References edit

  This article incorporates text in the public domain from page 235 of the 20th edition of Gray's Anatomy (1918)

External links edit